While I did this with a boomkin and 4 shamans, I'll try to throw my insight in here, too.

The only thing I really had any issues with was the stair event. Now, how I did this solo way before MB was I just pally tanked and had the group healer heal me. I BoL and judged on the elites while just throwing a low level concecrate and rank 1 (I think all I had was r1) holy shield when redoubt proc'd. I'd clear so fast that I'd usually have time for a full health/mana food stop before the next group spawned.

With my multibox team, I ran oom all the time, barely kept everyone healed. I managed to keep the little goblin and the captain alive, but the others died (lost little chunks of XP :-( ) while killing the boss at the bottom.